1. Field of the Invention
The present invention relates to a cleaning device for cleaning a body to be cleaned, such as a photosensitive body, a dip sheet used with such a cleaning device, a method for adhering such a dip sheet, a process cartridge and an image forming system.
2. Description of the Related Art
Generally, a known image forming system, or image forming apparatus, includes an image bearing member of a rotating drum type having a photo-conductive photosensitive layer at its outer peripheral surface is used, an electrostatic latent image is formed on the photosensitive layer while rotating the image bearing member, the electrostatic latent image is developed (visualized) with toner as a toner image, and then the toner image is transferred onto a transfer sheet. In such an image forming system, after a cycle of the image formation is finished, the residual toner (and other foreign matters) adhered to the surface of the image bearing member is removed from the image bearing member by a cleaning device.
As an example, the cleaning device comprises a cleaning blade for removing the residual toner remaining on the image bearing member while slidingly contacting with the image bearing member, a squeegee or dip sheet disposed below the cleaning blade and contacted with the image bearing member to receive the removed toner, and a waste toner reservoir for collecting the waste toner received by the squeegee sheet.
The cleaning blade and the squeegee sheet are arranged to contact the surface of the image bearing member, and, in particular, the squeegee sheet is attached to a predetermined position (referred to as "attachment surface" hereinafter) of the waste toner reservoir by a both-sided adhesive tape.
However, the waste toner reservoir is made of resin material and, thus, has an uneven and/or slightly deformed surface. Accordingly, if the squeegee sheet is merely stuck to the toner reservoir by the both-sided adhesive tape, undulation or sinuosity is generated at a free edge portion of the squeegee sheet which is contacted with the image bearing member, with the result that the free edge portion of the squeegee sheet does not closely contact with the surface of the image bearing member, thus causing a problem that the toner removed by the cleaning blade is received by the squeegee sheet less than perfectly that is, with reduced efficiency.
Further, when a charger roller (charger device of contact type) is used to charge the image bearing member, the contacting pressure between the charger roller and the image bearing member becomes great at both ends of the roller, and a small amount of toner which has escaped from the cleaning blade is compressed by the urging force of the charger roller, thus adhering to the surface of the image bearing member. Further, when the overlapped DC and AC voltages are applied to the charger roller, since the charger roller is vibrated, the toner which has escaped from the cleaning blade is compressed by the roller with stronger force, thus considerably contaminating the surface of the image bearing member with toner.
In order to eliminate the above drawback, the inventors conducted various tests and found that the above drawback was caused not only by the urging force of the charger roller against the image bearing member, but also by the urging force of the squeegee sheet against the image bearing member. Further, if the urging force of the squeegee sheet against the image bearing member is too great, the surface of the image bearing member will easily be damaged, with the result that the adhesion of the toner to the image bearing member (particularly, to both end portions of the image bearing member) is promoted.